Changes since the initial port

The following section lists changes to this file in mathlib3 and mathlib4 that occured after the initial port. Most recent changes are shown first. Hovering over a commit will show all commits associated with the same mathlib3 commit.

Changes in mathlib3

2d6f88c2

(last sync)

Changes in mathlib3port

mathlib3

mathlib3port

08b081ea

bump to nightly-2024-04-06-08

mathlib commit https://github.com/leanprover-community/mathlib/commit/65a1391a0106c9204fe45bc73a039f056558cb83

e34029c9

Diff

@@ -3,7 +3,7 @@ Copyright (c) 2020 Kevin Lacker. All rights reserved.
 Released under Apache 2.0 license as described in the file LICENSE.
 Authors: Kevin Lacker
 -/
-import Data.Nat.Fib
+import Data.Nat.Fib.Basic
 import Mathbin.Tactic.Linarith.Default
 
 #align_import imo.imo1981_q3 from "leanprover-community/mathlib"@"08b081ea92d80e3a41f899eea36ef6d56e0f1db0"

08b081ea

bump to nightly-2024-03-17-08

mathlib commit https://github.com/leanprover-community/mathlib/commit/65a1391a0106c9204fe45bc73a039f056558cb83

22f01ce4

Diff

@@ -174,7 +174,7 @@ theorem m_n_bounds {m n : ℕ} (h1 : NatPredicate N m n) : m ≤ fib K ∧ n ≤
         _ ≤ fib (K + 1) := fib_mono h6
   · have h7 : N < n := by
       have h8 : K + 2 ≤ k + 1 := succ_le_succ (not_lt.mp h2)
-      rw [← fib_add_two] at HK 
+      rw [← fib_add_two] at HK
       calc
         N < fib (K + 2) := HK
         _ ≤ fib (k + 1) := (fib_mono h8)
@@ -192,7 +192,7 @@ theorem k_bound {m n : ℤ} (h1 : ProblemPredicate N m n) : m ^ 2 + n ^ 2 ≤ M
   by
   have h2 : 0 ≤ m := h1.m_range.left.le
   have h3 : 0 ≤ n := h1.n_range.left.le
-  rw [← nat_abs_of_nonneg h2, ← nat_abs_of_nonneg h3] at h1 ; clear h2 h3
+  rw [← nat_abs_of_nonneg h2, ← nat_abs_of_nonneg h3] at h1; clear h2 h3
   obtain ⟨h4 : m.nat_abs ≤ fib K, h5 : n.nat_abs ≤ fib (K + 1)⟩ := m_n_bounds HK h1
   have h6 : m ^ 2 ≤ fib K ^ 2 := nat_abs_le_iff_sq_le.mp h4
   have h7 : n ^ 2 ≤ fib (K + 1) ^ 2 := nat_abs_le_iff_sq_le.mp h5
@@ -219,7 +219,7 @@ numbers in this range, and thus provide the maximum of `specified_set`.
 theorem imo1981_q3 : IsGreatest (specifiedSet 1981) 3524578 :=
   by
   have := fun h => @solution_greatest 1981 16 h 3524578
-  simp only [show fib (16 : ℕ) = 987 ∧ fib (16 + 1 : ℕ) = 1597 by norm_num [fib_add_two]] at this 
+  simp only [show fib (16 : ℕ) = 987 ∧ fib (16 + 1 : ℕ) = 1597 by norm_num [fib_add_two]] at this
   apply_mod_cast this <;> norm_num [problem_predicate_iff]
 #align imo1981_q3 imo1981_q3

08b081ea

bump to nightly-2023-09-24-06

mathlib commit https://github.com/leanprover-community/mathlib/commit/ce64cd319bb6b3e82f31c2d38e79080d377be451

5655435f

Diff

@@ -3,7 +3,7 @@ Copyright (c) 2020 Kevin Lacker. All rights reserved.
 Released under Apache 2.0 license as described in the file LICENSE.
 Authors: Kevin Lacker
 -/
-import Mathbin.Data.Nat.Fib
+import Data.Nat.Fib
 import Mathbin.Tactic.Linarith.Default
 
 #align_import imo.imo1981_q3 from "leanprover-community/mathlib"@"08b081ea92d80e3a41f899eea36ef6d56e0f1db0"

08b081ea

bump to nightly-2023-07-20-09

mathlib commit https://github.com/leanprover-community/mathlib/commit/8ea5598db6caeddde6cb734aa179cc2408dbd345

9c56d0dd

Diff

@@ -2,15 +2,12 @@
 Copyright (c) 2020 Kevin Lacker. All rights reserved.
 Released under Apache 2.0 license as described in the file LICENSE.
 Authors: Kevin Lacker
-
-! This file was ported from Lean 3 source module imo.imo1981_q3
-! leanprover-community/mathlib commit 08b081ea92d80e3a41f899eea36ef6d56e0f1db0
-! Please do not edit these lines, except to modify the commit id
-! if you have ported upstream changes.
 -/
 import Mathbin.Data.Nat.Fib
 import Mathbin.Tactic.Linarith.Default
 
+#align_import imo.imo1981_q3 from "leanprover-community/mathlib"@"08b081ea92d80e3a41f899eea36ef6d56e0f1db0"
+
 /-!
 # IMO 1981 Q3

08b081ea

bump to nightly-2023-07-17-03

mathlib commit https://github.com/leanprover-community/mathlib/commit/bf2428c9486c407ca38b5b3fb10b87dad0bc99fa

a159b65f

Diff

@@ -4,7 +4,7 @@ Released under Apache 2.0 license as described in the file LICENSE.
 Authors: Kevin Lacker
 
 ! This file was ported from Lean 3 source module imo.imo1981_q3
-! leanprover-community/mathlib commit 2d6f88c296da8df484d7f5b9ee1d10910ab473a2
+! leanprover-community/mathlib commit 08b081ea92d80e3a41f899eea36ef6d56e0f1db0
 ! Please do not edit these lines, except to modify the commit id
 ! if you have ported upstream changes.
 -/
@@ -14,6 +14,9 @@ import Mathbin.Tactic.Linarith.Default
 /-!
 # IMO 1981 Q3
 
+> THIS FILE IS SYNCHRONIZED WITH MATHLIB4.
+> Any changes to this file require a corresponding PR to mathlib4.
+
 Determine the maximum value of `m ^ 2 + n ^ 2`, where `m` and `n` are integers in
 `{1, 2, ..., 1981}` and `(n ^ 2 - m * n - m ^ 2) ^ 2 = 1`.

2d6f88c2

bump to nightly-2023-06-13-21

mathlib commit https://github.com/leanprover-community/mathlib/commit/9fb8964792b4237dac6200193a0d533f1b3f7423

829520ac

Diff

@@ -158,8 +158,6 @@ satisfying `nat_predicate m n N` are `fib K` and `fib (K+1)`, respectively.
 -/
 variable {K : ℕ} (HK : N < fib K + fib (K + 1)) {N}
 
-include HK
-
 theorem m_n_bounds {m n : ℕ} (h1 : NatPredicate N m n) : m ≤ fib K ∧ n ≤ fib (K + 1) :=
   by
   obtain ⟨k : ℕ, hm : m = fib k, hn : n = fib (k + 1)⟩ := h1.imp_fib m
@@ -190,8 +188,6 @@ We spell out the consequences of this result for `specified_set N` here.
 -/
 variable {M : ℕ} (HM : M = fib K ^ 2 + fib (K + 1) ^ 2)
 
-include HM
-
 theorem k_bound {m n : ℤ} (h1 : ProblemPredicate N m n) : m ^ 2 + n ^ 2 ≤ M :=
   by
   have h2 : 0 ≤ m := h1.m_range.left.le

2d6f88c2

bump to nightly-2023-06-09-07

mathlib commit https://github.com/leanprover-community/mathlib/commit/7e5137f579de09a059a5ce98f364a04e221aabf0

16afdc39

Diff

@@ -61,7 +61,6 @@ theorem m_le_n {m n : ℤ} (h1 : ProblemPredicate N m n) : m ≤ n :=
     calc
       1 = (n ^ 2 - m * n - m ^ 2) ^ 2 := h1.eq_one.symm
       _ = (n * (n - m) - m ^ 2) ^ 2 := by ring
-      
   have h4 : n * (n - m) - m ^ 2 < -1 := by nlinarith [h1.n_range.left]
   have h5 : 1 < (n * (n - m) - m ^ 2) ^ 2 := by nlinarith
   exact h5.ne h3
@@ -72,7 +71,6 @@ theorem eq_imp_1 {n : ℤ} (h1 : ProblemPredicate N n n) : n = 1 :=
     calc
       _ = (n ^ 2 - n * n - n ^ 2) ^ 2 := by simp [sq, mul_assoc]
       _ = 1 := h1.eq_one
-      
   eq_one_of_mul_eq_one_right h1.m_range.left.le this
 #align imo1981_q3.problem_predicate.eq_imp_1 Imo1981Q3.ProblemPredicate.eq_imp_1
 
@@ -89,14 +87,12 @@ theorem reduction {m n : ℤ} (h1 : ProblemPredicate N m n) (h2 : 1 < n) :
       calc
         _ < n := sub_lt_self n h1.m_range.left
         _ ≤ N := h1.n_range.right
-        
     exact ⟨h5, h6.le⟩
   -- eq_one:
   ·
     calc
       _ = (n ^ 2 - m * n - m ^ 2) ^ 2 := by ring
       _ = 1 := h1.eq_one
-      
 #align imo1981_q3.problem_predicate.reduction Imo1981Q3.ProblemPredicate.reduction
 
 end ProblemPredicate
@@ -174,12 +170,10 @@ theorem m_n_bounds {m n : ℕ} (h1 : NatPredicate N m n) : m ≤ fib K ∧ n ≤
       calc
         m = fib k := hm
         _ ≤ fib K := fib_mono h3
-        
     · have h6 : k + 1 ≤ K + 1 := succ_le_succ h3
       calc
         n = fib (k + 1) := hn
         _ ≤ fib (K + 1) := fib_mono h6
-        
   · have h7 : N < n := by
       have h8 : K + 2 ≤ k + 1 := succ_le_succ (not_lt.mp h2)
       rw [← fib_add_two] at HK 
@@ -187,7 +181,6 @@ theorem m_n_bounds {m n : ℕ} (h1 : NatPredicate N m n) : m ≤ fib K ∧ n ≤
         N < fib (K + 2) := HK
         _ ≤ fib (k + 1) := (fib_mono h8)
         _ = n := hn.symm
-        
     have h9 : n ≤ N := h1.n_le_N
     exact absurd h7 h9.not_lt
 #align imo1981_q3.m_n_bounds Imo1981Q3.m_n_bounds

2d6f88c2

bump to nightly-2023-06-07-01

mathlib commit https://github.com/leanprover-community/mathlib/commit/a3209ddf94136d36e5e5c624b10b2a347cc9d090

176da745

Changes in mathlib4

mathlib3

mathlib4

2d6f88c2

chore: superfluous parentheses part 2 (#12131)

Co-authored-by: Moritz Firsching <firsching@google.com>

d48d30ac

Diff

@@ -163,7 +163,7 @@ theorem m_n_bounds {m n : ℕ} (h1 : NatPredicate N m n) : m ≤ fib K ∧ n ≤
       rw [← fib_add_two] at HK
       calc
         N < fib (K + 2) := HK
-        _ ≤ fib (k + 1) := (fib_mono h8)
+        _ ≤ fib (k + 1) := fib_mono h8
         _ = n := hn.symm
     have h9 : n ≤ N := h1.n_le_N
     exact absurd h7 h9.not_lt

2d6f88c2

chore: bump dependencies (#10315)

Co-authored-by: Scott Morrison <scott.morrison@gmail.com>

ba9f2e5b

Diff

@@ -149,7 +149,7 @@ variable {K : ℕ} (HK : N < fib K + fib (K + 1)) {N}
 theorem m_n_bounds {m n : ℕ} (h1 : NatPredicate N m n) : m ≤ fib K ∧ n ≤ fib (K + 1) := by
   obtain ⟨k : ℕ, hm : m = fib k, hn : n = fib (k + 1)⟩ := h1.imp_fib m
   by_cases h2 : k < K + 1
-  · have h3 : k ≤ K := lt_succ_iff.mp h2
+  · have h3 : k ≤ K := Nat.lt_succ_iff.mp h2
     constructor
     · calc
         m = fib k := hm

2d6f88c2

refactor: decapitalize names in @[mk_iff] (#9378)

@[mk_iff] class MyPred now generates myPred_iff, not MyPred_iff
add Lean.Name.decapitalize
fix indentation and a few typos in the docs/comments.

Partially addresses issue #9129

5192777c

Diff

@@ -207,5 +207,5 @@ theorem imo1981_q3 : IsGreatest (specifiedSet 1981) 3524578 := by
   apply this
   · decide
   · decide
-  · norm_num [ProblemPredicate_iff]; decide
+  · norm_num [problemPredicate_iff]; decide
 #align imo1981_q3 imo1981_q3

2d6f88c2

chore: Move Data.Nat.Fib → Data.Nat.Fib.Basic (#8576)

This was postponed to after the Zeckendorf PR.

c9fe0984

Diff

@@ -4,7 +4,7 @@ Released under Apache 2.0 license as described in the file LICENSE.
 Authors: Kevin Lacker
 -/
 import Mathlib.Data.Int.Lemmas
-import Mathlib.Data.Nat.Fib
+import Mathlib.Data.Nat.Fib.Basic
 import Mathlib.Tactic.Linarith
 import Mathlib.Tactic.LinearCombination

2d6f88c2

chore: replace exact_mod_cast tactic with mod_cast elaborator where possible (#8404)

We still have the exact_mod_cast tactic, used in a few places, which somehow (?) works a little bit harder to prevent the expected type influencing the elaboration of the term. I would like to get to the bottom of this, and it will be easier once the only usages of exact_mod_cast are the ones that don't work using the term elaborator by itself.

Co-authored-by: Scott Morrison <scott.morrison@gmail.com>

693fd795

Diff

@@ -97,25 +97,25 @@ namespace NatPredicate
 
 variable {N}
 
-nonrec theorem m_le_n {m n : ℕ} (h1 : NatPredicate N m n) : m ≤ n := by exact_mod_cast h1.m_le_n
+nonrec theorem m_le_n {m n : ℕ} (h1 : NatPredicate N m n) : m ≤ n := mod_cast h1.m_le_n
 #align imo1981_q3.nat_predicate.m_le_n Imo1981Q3.NatPredicate.m_le_n
 
-nonrec theorem eq_imp_1 {n : ℕ} (h1 : NatPredicate N n n) : n = 1 := by exact_mod_cast h1.eq_imp_1
+nonrec theorem eq_imp_1 {n : ℕ} (h1 : NatPredicate N n n) : n = 1 := mod_cast h1.eq_imp_1
 #align imo1981_q3.nat_predicate.eq_imp_1 Imo1981Q3.NatPredicate.eq_imp_1
 
 nonrec theorem reduction {m n : ℕ} (h1 : NatPredicate N m n) (h2 : 1 < n) :
     NatPredicate N (n - m) m := by
   have : m ≤ n := h1.m_le_n
-  exact_mod_cast h1.reduction (by exact_mod_cast h2)
+  exact mod_cast h1.reduction (mod_cast h2)
 #align imo1981_q3.nat_predicate.reduction Imo1981Q3.NatPredicate.reduction
 
-theorem n_pos {m n : ℕ} (h1 : NatPredicate N m n) : 0 < n := by exact_mod_cast h1.n_range.left
+theorem n_pos {m n : ℕ} (h1 : NatPredicate N m n) : 0 < n := mod_cast h1.n_range.left
 #align imo1981_q3.nat_predicate.n_pos Imo1981Q3.NatPredicate.n_pos
 
-theorem m_pos {m n : ℕ} (h1 : NatPredicate N m n) : 0 < m := by exact_mod_cast h1.m_range.left
+theorem m_pos {m n : ℕ} (h1 : NatPredicate N m n) : 0 < m := mod_cast h1.m_range.left
 #align imo1981_q3.nat_predicate.m_pos Imo1981Q3.NatPredicate.m_pos
 
-theorem n_le_N {m n : ℕ} (h1 : NatPredicate N m n) : n ≤ N := by exact_mod_cast h1.n_range.right
+theorem n_le_N {m n : ℕ} (h1 : NatPredicate N m n) : n ≤ N := mod_cast h1.n_range.right
 set_option linter.uppercaseLean3 false in
 #align imo1981_q3.nat_predicate.n_le_N Imo1981Q3.NatPredicate.n_le_N

2d6f88c2

chore: bump to v4.3.0-rc2 (#8366)

PR contents

This is the supremum of

#8284
#8056
#8023
#8332
#8226 (already approved)
#7834 (already approved)

along with some minor fixes from failures on nightly-testing as Mathlib master is merged into it.

Note that some PRs for changes that are already compatible with the current toolchain and will be necessary have already been split out: #8380.

I am hopeful that in future we will be able to progressively merge adaptation PRs into a bump/v4.X.0 branch, so we never end up with a "big merge" like this. However one of these adaptation PRs (#8056) predates my new scheme for combined CI, and it wasn't possible to keep that PR viable in the meantime.

Lean PRs involved in this bump

In particular this includes adjustments for the Lean PRs

leanprover/lean4#2778

We can get rid of all the

local macro_rules | `($x ^ $y) => `(HPow.hPow $x $y) -- Porting note: See issue [lean4#2220](https://github.com/leanprover/lean4/pull/2220)

macros across Mathlib (and in any projects that want to write natural number powers of reals).

leanprover/lean4#2722

Changes the default behaviour of simp to (config := {decide := false}). This makes simp (and consequentially norm_num) less powerful, but also more consistent, and less likely to blow up in long failures. This requires a variety of changes: changing some previously by simp or norm_num to decide or rfl, or adding (config := {decide := true}).

leanprover/lean4#2783

This changed the behaviour of simp so that simp [f] will only unfold "fully applied" occurrences of f. The old behaviour can be recovered with simp (config := { unfoldPartialApp := true }). We may in future add a syntax for this, e.g. simp [!f]; please provide feedback! In the meantime, we have made the following changes:

switching to using explicit lemmas that have the intended level of application
(config := { unfoldPartialApp := true }) in some places, to recover the old behaviour
Using @[eqns] to manually adjust the equation lemmas for a particular definition, recovering the old behaviour just for that definition. See #8371, where we do this for Function.comp and Function.flip.

This change in Lean may require further changes down the line (e.g. adding the !f syntax, and/or upstreaming the special treatment for Function.comp and Function.flip, and/or removing this special treatment). Please keep an open and skeptical mind about these changes!

Co-authored-by: leanprover-community-mathlib4-bot <leanprover-community-mathlib4-bot@users.noreply.github.com> Co-authored-by: Scott Morrison <scott.morrison@gmail.com> Co-authored-by: Eric Wieser <wieser.eric@gmail.com> Co-authored-by: Mauricio Collares <mauricio@collares.org>

40b64f79

Diff

@@ -129,7 +129,7 @@ theorem imp_fib {n : ℕ} : ∀ m : ℕ, NatPredicate N m n → ∃ k : ℕ, m =
   obtain (rfl : 1 = n) | (h4 : 1 < n) := (succ_le_iff.mpr h2.n_pos).eq_or_lt
   · use 1
     have h5 : 1 ≤ m := succ_le_iff.mpr h2.m_pos
-    simpa [fib_one, fib_two] using (h3.antisymm h5 : m = 1)
+    simpa [fib_one, fib_two, (by decide : 1 + 1 = 2)] using (h3.antisymm h5 : m = 1)
   · obtain (rfl : m = n) | (h6 : m < n) := h3.eq_or_lt
     · exact absurd h2.eq_imp_1 (Nat.ne_of_gt h4)
     · have h7 : NatPredicate N (n - m) m := h2.reduction h4
@@ -205,5 +205,7 @@ theorem imo1981_q3 : IsGreatest (specifiedSet 1981) 3524578 := by
   have := fun h => @solution_greatest 1981 16 h 3524578
   norm_num at this
   apply this
-  norm_num [ProblemPredicate_iff]
+  · decide
+  · decide
+  · norm_num [ProblemPredicate_iff]; decide
 #align imo1981_q3 imo1981_q3

2d6f88c2

feat: fix norm num with arguments (#6600)

norm_num was passing the wrong syntax node to elabSimpArgs when elaborating, which essentially had the effect of ignoring all arguments it was passed, i.e. norm_num [add_comm] would not try to commute addition in the simp step. The fix itself is very simple (though not obvious to debug!), probably using TSyntax more would help avoid such issues in future.

Due to this bug many norm_num [blah] became rw [blah]; norm_num or similar, sometimes with porting notes, sometimes not, we fix these porting notes and other regressions during the port also.

Interestingly cancel_denoms uses norm_num [<- mul_assoc] internally, so cancel_denoms also got stronger with this change.

49a849ef

Diff

@@ -203,8 +203,7 @@ numbers in this range, and thus provide the maximum of `specifiedSet`.
 -/
 theorem imo1981_q3 : IsGreatest (specifiedSet 1981) 3524578 := by
   have := fun h => @solution_greatest 1981 16 h 3524578
-  simp only [show fib (16 : ℕ) = 987 ∧ fib (16 + 1 : ℕ) = 1597 by norm_num [fib_add_two]] at this
-  apply_mod_cast this trivial trivial
-  rw [ProblemPredicate_iff]
-  norm_num
+  norm_num at this
+  apply this
+  norm_num [ProblemPredicate_iff]
 #align imo1981_q3 imo1981_q3

2d6f88c2

chore: script to replace headers with #align_import statements (#5979)

depends on: #5966

Co-authored-by: Eric Wieser <wieser.eric@gmail.com> Co-authored-by: Scott Morrison <scott.morrison@gmail.com>

89aa3a3b

Diff

@@ -2,17 +2,14 @@
 Copyright (c) 2020 Kevin Lacker. All rights reserved.
 Released under Apache 2.0 license as described in the file LICENSE.
 Authors: Kevin Lacker
-
-! This file was ported from Lean 3 source module imo.imo1981_q3
-! leanprover-community/mathlib commit 2d6f88c296da8df484d7f5b9ee1d10910ab473a2
-! Please do not edit these lines, except to modify the commit id
-! if you have ported upstream changes.
 -/
 import Mathlib.Data.Int.Lemmas
 import Mathlib.Data.Nat.Fib
 import Mathlib.Tactic.Linarith
 import Mathlib.Tactic.LinearCombination
 
+#align_import imo.imo1981_q3 from "leanprover-community/mathlib"@"2d6f88c296da8df484d7f5b9ee1d10910ab473a2"
+
 /-!
 # IMO 1981 Q3

2d6f88c2

chore: remove occurrences of semicolon after space (#5713)

This is the second half of the changes originally in #5699, removing all occurrences of ; after a space and implementing a linter rule to enforce it.

In most cases this 2-character substring has a space after it, so the following command was run first:

find . -type f -name "*.lean" -exec sed -i -E 's/ ; /; /g' {} \;

The remaining cases were few enough in number that they were done manually.

c795bd35

Diff

@@ -180,7 +180,7 @@ variable {M : ℕ} (HM : M = fib K ^ 2 + fib (K + 1) ^ 2)
 theorem k_bound {m n : ℤ} (h1 : ProblemPredicate N m n) : m ^ 2 + n ^ 2 ≤ M := by
   have h2 : 0 ≤ m := h1.m_range.left.le
   have h3 : 0 ≤ n := h1.n_range.left.le
-  rw [← natAbs_of_nonneg h2, ← natAbs_of_nonneg h3] at h1 ; clear h2 h3
+  rw [← natAbs_of_nonneg h2, ← natAbs_of_nonneg h3] at h1; clear h2 h3
   obtain ⟨h4 : m.natAbs ≤ fib K, h5 : n.natAbs ≤ fib (K + 1)⟩ := m_n_bounds HK h1
   have h6 : m ^ 2 ≤ (fib K : ℤ) ^ 2 := Int.natAbs_le_iff_sq_le.mp h4
   have h7 : n ^ 2 ≤ (fib (K + 1) : ℤ) ^ 2 := Int.natAbs_le_iff_sq_le.mp h5

2d6f88c2

chore: cleanup porting notes about refine_struct (#5542)

Replace some porting notes about refine_struct with uses of refine'. We only really miss refine_struct in situations where we later used pi_instance_derive_field.

I also exercised some editorial discretion to remove some porting notes about refine_struct when the original usage was (in my opinion) obfuscatory relative to just writing out the fields. (We shouldn't be using alternatives to handle different fields!)

Co-authored-by: Scott Morrison <scott.morrison@gmail.com>

955998cf

Diff

@@ -74,7 +74,6 @@ theorem reduction {m n : ℤ} (h1 : ProblemPredicate N m n) (h2 : 1 < n) :
   obtain (rfl : m = n) | (h3 : m < n) := h1.m_le_n.eq_or_lt
   · have h4 : m = 1 := h1.eq_imp_1
     exact absurd h4.symm h2.ne
-  -- Porting note: Original proof used `refine_struct { n_range := h1.m_range .. }`
   exact
     { n_range := h1.m_range
       m_range := by

2d6f88c2

feat: port RingTheory.Polynomial.Eisenstein.IsIntegral (#5302)

Fix also some names in RingTheory.Polynomial.Eisenstein.Basic that are in the wrong namespace.

c511043c

Diff

@@ -11,6 +11,7 @@ Authors: Kevin Lacker
 import Mathlib.Data.Int.Lemmas
 import Mathlib.Data.Nat.Fib
 import Mathlib.Tactic.Linarith
+import Mathlib.Tactic.LinearCombination
 
 /-!
 # IMO 1981 Q3
@@ -57,20 +58,14 @@ variable {N}
 
 theorem m_le_n {m n : ℤ} (h1 : ProblemPredicate N m n) : m ≤ n := by
   by_contra h2
-  have h3 : 1 = (n * (n - m) - m ^ 2) ^ 2 := by
-    calc
-      1 = (n ^ 2 - m * n - m ^ 2) ^ 2 := h1.eq_one.symm
-      _ = (n * (n - m) - m ^ 2) ^ 2 := by ring
+  have h3 : 1 = (n * (n - m) - m ^ 2) ^ 2 := by linear_combination - h1.eq_one
   have h4 : n * (n - m) - m ^ 2 < -1 := by nlinarith [h1.n_range.left]
   have h5 : 1 < (n * (n - m) - m ^ 2) ^ 2 := by nlinarith
   exact h5.ne h3
 #align imo1981_q3.problem_predicate.m_le_n Imo1981Q3.ProblemPredicate.m_le_n
 
 theorem eq_imp_1 {n : ℤ} (h1 : ProblemPredicate N n n) : n = 1 :=
-  haveI : n * (n * (n * n)) = 1 := by
-    calc
-      _ = (n ^ 2 - n * n - n ^ 2) ^ 2 := by simp [sq, mul_assoc]
-      _ = 1 := h1.eq_one
+  have : n * (n * (n * n)) = 1 := by linear_combination h1.eq_one
   eq_one_of_mul_eq_one_right h1.m_range.left.le this
 #align imo1981_q3.problem_predicate.eq_imp_1 Imo1981Q3.ProblemPredicate.eq_imp_1
 
@@ -89,10 +84,7 @@ theorem reduction {m n : ℤ} (h1 : ProblemPredicate N m n) (h2 : 1 < n) :
             _ < n := sub_lt_self n h1.m_range.left
             _ ≤ N := h1.n_range.right
         exact ⟨h5, h6.le⟩
-      eq_one := by
-        calc
-          _ = (n ^ 2 - m * n - m ^ 2) ^ 2 := by ring
-          _ = 1 := h1.eq_one }
+      eq_one := by linear_combination h1.eq_one }
 #align imo1981_q3.problem_predicate.reduction Imo1981Q3.ProblemPredicate.reduction
 
 end ProblemPredicate

2d6f88c2

feat: port MeasureTheory.Function.ConditionalExpectation.Basic (#4898)

529b276a

`imo.imo1981_q3` ⟷ `Archive.Imo.Imo1981Q3`

Changes since the initial port

Changes in mathlib3

Changes in mathlib3port

Changes in mathlib4

PR contents

Lean PRs involved in this bump

leanprover/lean4#2778

leanprover/lean4#2722

leanprover/lean4#2783

Dependencies 3 + 193

imo.imo1981_q3 ⟷ Archive.Imo.Imo1981Q3

Changes since the initial port

Changes in mathlib3

Changes in mathlib3port

Changes in mathlib4

PR contents

Lean PRs involved in this bump

leanprover/lean4#2778

leanprover/lean4#2722

leanprover/lean4#2783

Dependencies 3 + 193

`imo.imo1981_q3` ⟷ `Archive.Imo.Imo1981Q3`